Tektronix 491 Product Modification

B. TO REMOVE THE BAND
11
C
11
OSCILLATOR
( )
( )
( )
(
)
( )
( )
( )
( )
( )
1. Unsolder the Band
11
C
11
oscillator filament leads*. One from the Band 'B'
oscillator and one from the oscillator connector board.
2.
Unsolder band C B+ lead (orange wire) from connector board.
3. Loosen the
set screws on the Band
11
C
11
oscillator .drive flexible coupler*.
4. Loosen the collet on the Band
11
A
11
oscillator tuning shaft.
5. Loosen the set screw (j) (See Fig. 2 page 9) that fastens the front band svJitch
lever to the coupling rod. @ .
6. Remove the four 4-40 screws @,; that fasten the dial housing to the
front oscillator mounting plate* ;3·, and remove the dial housing.
7.
Remove the two screws that fas ten the back end of the Band
11
C
11
osci 11 a tor
to the rear sup port bracket (6--;.
,_...,
8. Observe the orientation of the front mounting plate (3J , and remove two
screws, one flat head and one pan head, that fasten the Band
11
C
11
oscillator to the front mounting bracket.
9. Remove the two socket head screws ~6) that fasten the front mounting
Plate to the Band
11
A
11
oscillator, and remove the Band
11
C
11
oscillator,
and the front mounting plate*.
C. TO INSTALL NEW BAND
11
C
11
OSCILLATOR
( )
1.
Temporari k remove the two screws r28J that fas ten the band switch
bracket ® to the Band
11
B
11
osci l'lftor rear support. ®
Fas ten the Band
11
C
11
osci 11 a tor rear support angle bracket @ over the
band switch
bracket with the hardware just removed.
( ) 2. Fasten the
new front oscillator mountil']g plate m to the Band
11
A
11
oscillator using the hardware removed in Step B..:-g:
( ) 3. Reins tall the di al housing by ins tall i ng the two top screws that fas ten
the di al housing to the
new front oscil 1 a tor mounting pl ate. DO NOT
TIGHTEN COLLET ON BAND A OSCILLATOR.
( ) 4. Fasten the Band C oscillator front angle bracket to the bottom holes
of the dial housing and replace the bottom left mounting screw with
the button head screw.
~
* Discard. Part will not be used in new assembly.
Page 4 of 9 050-0692- O 2

Tektronix 491 Specifications

General

Brand	Tektronix
Model	491
Category	Measuring Instruments
Language	English